This invention relates to compositions for reducing adverse reactions of the skin to chemicals and compositions that contact the skin, e.g., topical cosmetic and pharmaceutical compositions, and for reducing such adverse reactions caused by certain kinds of physical contact.
Exposure of human skin to chemicals contained in topical cosmetic and pharmaceutical compositions can result in adverse reactions to the skin, including irritation response and contact sensitization of the skin. As used herein, the term cosmetic and pharmaceutical compositions is used in the widest sense of the term, and encompasses any composition that is applied to the skin for a beneficial effect. As used herein, contact sensitization of the skin refers to adverse systemic immunological reactions of the skin, e.g., itching, burning, swelling or redness. Irritation response of the skin involves similar symptoms in which the systemic immune system plays no role.
A small, but significant segment of the population is particularly prone to such irritation response and contact sensitization. As a consequence, the use of a wide variety of topical preparations for the skin by this segment of the population is, at best, an unpleasant task. For example, compositions containing paramino benzoic acid (e.g., sunscreens) or Balsam of Peru are known to cause contact sensitization, and certain chemicals, e.g., vasodilators and surfactants are known to cause irritation response when used by certain persons.
In addition, certain types of physical contact with human skin can cause irritation response of the skin. For example, the removal of hair from human skin by waxing methods is known to cause irritation to most, if not all, persons who have waxing treatments. Hereinafter, the types of physical contact that cause irritation response of human skin are referred to as "contact physical irritants."